/*
 * Copyright (c) 2007-2012, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: FuncCurrent.java,v 1.2.4.1 2005/09/14 19:53:44 jeffsuttor Exp $
 */
package com.sun.org.apache.xpath.internal.functions;

import com.sun.org.apache.xml.internal.dtm.DTM;
import com.sun.org.apache.xml.internal.dtm.DTMIterator;
import com.sun.org.apache.xpath.internal.XPathContext;
import com.sun.org.apache.xpath.internal.axes.LocPathIterator;
import com.sun.org.apache.xpath.internal.axes.PredicatedNodeTest;
import com.sun.org.apache.xpath.internal.objects.XNodeSet;
import com.sun.org.apache.xpath.internal.objects.XObject;
import com.sun.org.apache.xpath.internal.axes.SubContextList;
import com.sun.org.apache.xpath.internal.patterns.StepPattern;
import com.sun.org.apache.xalan.internal.res.XSLMessages;
import com.sun.org.apache.xalan.internal.res.XSLTErrorResources;

/**
 * Execute the current() function.
 * @xsl.usage advanced
 */
public class FuncCurrent extends Function {
    static final long serialVersionUID = 5715316804877715008L;

    /**
     * Execute the function.  The function must return
     * a valid object.
     * @param xctxt The current execution context.
     * @return A valid XObject.
     *
     * @throws javax.xml.transform.TransformerException
     */
    public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException {

        SubContextList subContextList = xctxt.getCurrentNodeList();
        int currentNode = DTM.NULL;

        if (null != subContextList) {
            if (subContextList instanceof PredicatedNodeTest) {
                LocPathIterator iter = ((PredicatedNodeTest) subContextList).getLocPathIterator();
                currentNode = iter.getCurrentContextNode();
            } else if (subContextList instanceof StepPattern) {
                throw new RuntimeException(XSLMessages.createMessage(XSLTErrorResources.ER_PROCESSOR_ERROR, null));
            }
        } else {
            // not predicate => ContextNode == CurrentNode
            currentNode = xctxt.getContextNode();
        }
        return new XNodeSet(currentNode, xctxt.getDTMManager());
    }

    /**
     * No arguments to process, so this does nothing.
     */
    public void fixupVariables(java.util.Vector vars, int globalsSize) {
        // no-op
    }

}
